Tactical voting

I've never voted tactically before. Mainly because up until now it would always have been irrelevant to the outcome and partly because I think it's important to register support for the Greens. But this time there is the possibility of a non-Tory candidate winning in my constituency. So, should I vote tactically and if so what do I need to know?

There was a good article in Politico last week on the relatively naivety of British voters when it comes to tactical voting and I don't want to fall in a similar trap - https://www.politico.eu/article/britain-conservatives-tories-uk-election-tactical-voting/ .

The basics seem to be find out who is (potentially) polling second and give them your vote. But this isn't straight forward given the large swings since 2019, changes in some electoral boundaries since then - including a small change in my constituency, and limited information about current polling intentions in a given constituency.

For example, in Didcot & Wantage (my constituency) at at least three different tactical voting options are offered by three different anti-Tory web sites:
https://tactical.vote/didcot-and-wantage/ recommends voting Liberal
https://www.getvoting.org/constituency/E14001197 recommends voting Labour
and https://tacticalvote.co.uk/#DidcotWantage say it's too early to tell

In addition Electoral calculus predict a potential Labour win https://www.electoralcalculus.co.uk/fcgi-bin/calcwork23.py?seat=Didcot+and+Wantage

So, any tactical voting tips?

Wait till as close to the end as possible and then pick your vote. There will also be stopthetories.vote